The powerful solar winds that buffet the earth’s atmosphere cause the shimmering northern lights of the aurora borealis, as well as many of the blackouts that plague our electrical systems.

“We’ve seen back in March of 1989, a powerful geomagnetic storm brought the grid down in Montreal and Quebec," recalled William Murtagh at the National Space Weather Prediction Center. "We had issues with some of our nuclear power plants in 1991. As recently as 2003, a big geomagnetic storm during that period we call the Halloween Storms produced a blackout in Malmo, Sweden, and damaged transformers in the Escombe Network in South Africa.”

The Prediction Center in Boulder, Colorado keeps an eye on the sun, and provides continually updated forecasts to more than 40,000 utility companies, government agencies, the satellite industry, commercial aviation and GPS users.

The typical solar forecast is hot, sunny and worry-free. But sometimes, satellites positioned near the sun observe giant orange geysers. These eruptions can generate magnetized winds, called coronal mass ejections, which blast into space.

It generally takes at least half a day for one of these solar storms to reach the earth, so at first, forecasters issue a “watch.” Murtagh compares it to a terrestrial storm watch, "somewhat like a hurricane watch when there’s a hurricane sitting somewhere off shore of Miami and it’s a couple of days out.”

In the final hour of its journey toward Earth, the storm engulfs a special satellite that provides crucial new data about its power and scope. Then, Murtagh says, forecasters race to send an update.

“So we can give all the folks that we gave a heads-up to a day or two earlier, we can say okay, it’s worse than we expected, it’s as expected, or maybe it’s a bit of a dud and is not going to be the impact we thought it might have here on earth.”

When a storm is not a dud

On a scale of 1 to 5, most solar storms are Class 2 or lower, so a bit of a dud, and last less than a day. For Class 5 storms, utility companies route power away from sensitive equipment and intensive geomagnetic activity. Because short-term blackouts are possible in powerful storms, hospitals, airports and other emergency centers are urged to keep backup generators ready.

But these procedures might not be enough to get us through a Class 5 PLUS storm. Murtagh points to the Carrington Event, a massive solar storm that hit the earth in 1859. It created Aurora lights that were seen not only near the poles, but close to the equator -- in Cuba, Santiago, Chile, and Hawaii. And it wreaked havoc with telegraphs, the main electrical device of the time.

“The geomagnetic storm might have been three times, four, or up to ten times as big as anything we’ve seen since. So what does that mean? What does that translate to, in our critical infrastructure, especially the power grid?”

To investigate concerns like these, the Idaho National Laboratorymaintains high voltage transformers, so massive, they stand twice as tall as a man. Cyber Security Researcher Scott McBride said his teams occasionally zap these transformers with geomagnetic currents. Their experiments indicate that technicians could monitor individual transformers during solar storms, to reduce the chance that they’ll be harmed.

But if a Carrington-sized event hit next week, all bets are off. “It could be several continents," McBride said. "It could be planetary in scale.”

An event that size would be so overwhelming, McBride predicts that fluctuating current loads would destroy many transformers and it would take a long time to replace them.

“Extra high voltage transformers have lead times typically from 18 to 24 months, so if we lost 10 extra high voltage transformers in the U.S., we could have people out of power for six months, a year, up to two years.”

Plan B

McBride says engineers are developing a transformer that could replace a damaged unit in days, rather than months. And sophisticated grounding systems can protect equipment. But these steps will cost time and money.

So what if, next week, the Space Weather Prediction Center issues a red alert - a Carrington Event - 30 minutes from earth? McBride said there’s one more backup plan: “Turning the power grid off would certainly protect it from a geomagnetic disturbance, but the socioeconomic impacts of de-energizing the power grid are so huge, it would actually be very difficult for someone to make that decision.”

All together, these experts say, it’s time for world leaders, power companies and major power users to plan ahead, so that a world that depends on electricity can come together, to weather a solar superstorm.